1. Field of the Invention
The methods, apparatuses and articles described herein generally relate to automatic data collection (ADC) devices such as readers capable of reading automatic data collection media, for example optically reading machine-readable symbols (e.g., barcode symbols, area or matrix symbols, or stacked symbols). In particular, the methods, apparatuses and articles described herein facilitate machine-readable symbol acquisition in a cluttered environment, for example where two or more objects such as machine-readable symbols are in the field-of-view of the machine-readable symbol reader.
2. Description of the Related Art
The ADC field is generally directed to the use of devices for automatically capturing data typically encoded in media such as machine-readable symbols or radio frequency identification (RFID) tags carried by one or more items to which the encoded data typically relates.
A variety of ADC media and ADC devices for reading such ADC media are ubiquitous and well-known. For example, machine-readable symbol readers for optically reading machine-readable symbols such as barcode symbols, area or matrix symbols, or stacked symbols, are common in a large variety of retail, warehouse and shipping environments. Such machine-readable symbol readers are commonly referred to as “barcode” readers, even though they may be capable of reading machine-readable symbols other than barcodes.
The readers may be fixed, such as those typically found at many grocery or supermarket checkout stands where the item bearing the machine-readable symbol is passed over the reader. Handheld optical readers are also common. For example, wand type readers where the operator moves the optical reader across the machine-readable symbol. For other handheld readers, the operator generally aims the optical reader at the desired machine-readable symbol. The operator may optionally activate a trigger or other switch to cause the reader to read the machine-readable symbol.
Machine-readable symbol readers may take the form of optical scanners, for example, which scan a light such as a laser beam across the machine-readable symbol. Alternatively, optical readers may take the form of an imager which captures an image of the machine-readable symbol using a one- or two-dimensional image capture device to capture light reflected from the machine-readable symbol. Such light is typically provided by a flood illumination system of the machine-readable symbol reader.
The successful adoption and use of ADC devices such as machine-readable symbol readers face a number of problems. For example, such devices may be difficult to operate by a novice, particularly where the device is handheld and requires the operator to correctly space the machine-readable reader with respect to the item bearing the machine-readable symbol to be read. While many attempts have been made to improve the depth-of-field of machine-readable symbol readers, some degree of proper spacing is still typically necessary. Another problem occurs when the machine-readable symbol reader is used in a crowded environment, for example where two or more objects may be within the field-of-view of the machine-readable symbol reader. In such a situation, the operator typically will not be certain which one of the objects the machine-readable symbol reader will decode. Such an environment may, for example, occur in the guise of a standardized form, which may include text, numbers, pictures, graphics, and one or more machine-readable symbols.
Improved methods and apparatuses to address these problems would be beneficial to the ADC industry, as well as potential users of ADC devices.